The cover piece for a suction box for fleece dewatering in accordance with current practice, can be positioned transverse to the running direction of an endlessly circulating conveyor for a fleece made of a pulp material. This cover piece has a plurality of parallel dewatering passages or slots inclined to the running direction of the conveyor belt and located on both sides of the medium plane of the cover piece.
In this prior art cover piece the slots are arranged at a 45.degree. angle to the running direction of the conveyor belt so that they are distributed symmetrically and on both sides of the cover piece medium plane.
With such inclined slots a tensioning action is exerted on the conveyor belt for the fleece (i.e. a dewatering screen or paper making felt) transverse to the running direction.
In the cover piece most often used heretofore a plastic material is used in construction so that a comparatively rapid wearing process is effected and the cover piece fairly quickly loses its ability to function properly.
With a ceramic construction, of course, the cover piece is practically completely free of wear but there is much more wear on the conveyor belt (felt or wire screen) especially at the transition region at the slot ends from the straight slot wall to a rounded slot wall. The transition regions can only be made by hand so that irregularities in the structure of the transition region cannot be avoided.